Process for removing sulfur from petroleum oils and synthesizing mercaptans



Sept. 5, 1967 V J ENG ET AL 3,340,184

PROCESS FOR REMOVING SULFUR FROM PETROLEUM OILS AND SYNTHESIZING MERCAPTANS Filed Oct. 30, 1964 OLEFIN a H28 5 4 36 HEATING on. 26

32 \SEPARATOR I2 28 MERCAPTAN \STRIPPER REACTOR-s. l8

ou-:F|N

' 1 24 HEATING on.

pnooucr FIG. l

NAPHTHA OLEFIN 5e OLEFIN REACTOR r- NAPHTHA 4s 52 66 5s "LSTEAM Q 4 4 i 68 .OLEF IN 8 MERCAPTAN C AN Jackson Eng John L. T'tedje Inventors Pofenr Attorney United States Patent 3,340,184 PROCESS FOR REMOVING SULFUR FROM PETRO- LEUM OILS AND SYNTHESIZING MERCAP- TANS Jackson Eng and John L. Tiedje, Sarnia, Ontario, Canada, assignors to Esso Research and Engineering Company, a corporation of Delaware Filed Oct. 30, 1964, Ser. No. 407,731 Claims. (Cl. 208-238) ABSTRACT OF THE DISCLOSURE Process for desulfurizing hydrocarbon distillates boiling in the range of 90800 F. and for recovering mercaptans including the steps of passing the distillate and an olefin over a sulfided cobalt molybdate catalyst and separating and recovering desulfurized distillate and mercaptan.

This invention relates to a process for desulfurizing hydrocarbon distillates and at the same time synthesizing mercaptans.

Many processes are known for desulfurizing hydrocarbon oils such as fuels and lubricating oils. The sulfur compounds in hydrocarbon liquids are objectionable because they are corrosive and have an objectionable odor. In gasolines, high sulfur is undesirable because it reduces the effectiveness of tetraethyl lead. Also, such gasolines have undesirable odor and gum formation tendencies. In fuel oils the sulfur burns to sulfur dioxide which is highly corrosive and foul smelling. Mercaptan sulfur in gasoline, fuel oil, lubricating oils, etc., is bad but mercaptan compounds are useful compounds.

The conventional process for manufacturing mercaptan comprises a separate unit for producing H S and a separate reactor system for reacting H 8 and an olefin.

According to the present invention, high sulfur hydrocarbons are mixed with an olefin or olefins c rr and this mixture is passed at an elevated temperature and superatmospheric pressure over a catalyst to remove sulfur by converting it to hydrogen sulfide which in the presence of the catalyst combines or reacts with the added olefin or olefins to produce a mercaptan or mercaptans. These two reactions take place in one stage or in one reactor. No H 3 recovery step is required. The molecular specie of the mercaptan produced is controlled by the selection of the olefin type and molecular weight. The present invention is a one-step process which combines desulfurization of a hydrocarbon distillate and the synthesis of mercaptans. The catalyst is sulfided cobalt molybdate on alumina.

The process for desulfurizing hydrocarbon oils is carried out with an olefin which is preferably selected to have a boiling point different from that of the hydrocarbon oil to be treated and desulfurized so as to form a mercaptan from the olefin and the released sulfur material which mercaptan has a boiling point different from that of the oil to be desulfurized so that the mercaptan may preferably be easily separated and recovered in a single fractionation. The olefin selectedalways has a boiling point lower than the mercaptan formed which facilitates separation of the olefin and mercaptan formed. Where the oil fractiton to be desulfurized is a relatively narrow fraction, the selection of an olefin to be added is relatively easy as the olefin is selected to form a mercaptan having a boiling point which is higher or lower than the boiling range of the fraction. For example, when desulfurizing a heavy naphtha having a boiling range of about 300 F. to 410 F., a C olefin may be used to form amyl mercaptans having a boiling point range below that of the heavy naphtha. Instead of a heavy naphtha, the C 3,340,184 Patented Sept. 5, 1967 olefin may be added to a light naphtha fraction having a lower boiling range than about 200 F. which is lower boiling than the amyl mercaptans formed during desulfurization.

In the drawings:

FIG. 1 represents one form of apparatus for carrying out the invention in a process wherein the treated oil has a higher boiling point than the mercaptan produced; and

FIG. 2 represents another form of apparatus for carry ing out the invention in a process wherein the mercaptan produced has a higher boiling point than the treated hydrocarbon distillate.

Referring now to FIG. 1 of the drawing, the reference character 10 designates a reactor vessel containing a fixed bed of catalyst which is sulfided cobalt molybdate and is made 'by passing H 8 gas over cobalt molybdate catalyst on an alumina base for about 2 to 16 hours at a temperature of about 600 F. at 200 p.s.i.g. pressure. Sulfiding may be carried out in other ways. The amount of sulfur added during sulfiding may vary from about 200% up to about 1500% of the stoichiornetric quantity necessary to convert the cobalt oxide and molybdenum oxide to the corresponding sulfides. The catalyst may contain 5-25 wt. percent of cobalt oxide and molybdenum oxide with the ratio of cobalt oxide to the molybdenum oxide in the range of from about 1:5 to about 5:1 supported on adsorptive or activated alumina which may contain up to 25 wt. percent silica. The alumina forms about 50 to wt. percent of the unsulfided cobalt molybdate catalyst.

A hydrocarbon distillate having a boiling range between about 300 F. and 700 P. such as a virgin gas oil is passed through line 12 at a temperature of between about 400 F. and 700 F., preferably 500 F., and into line 14 containing an added olefin and recycle hydrogen sulfide. The olefin may be one selected from the group comprising C olefin to C olefins. The resulting mixture is introduced into the top of the reactor 10 for passage over the catalyst therein. The catalyst is sulfided cobalt molybdate on alumina and before sulfiding it contains 3.5% cobalt oxide (C00), 12.5% molybdenum oxide (M00 on alumina. The catalyst is in the form of diameter extrudate of approximately A" long.

The pressure in the reactor 10 is maintained between about p.s.i.g. and 1000 p.s.i.g. The olefin and heating oil are passed through the sulfided cobalt molybdatealumina at a rate of 1 volume of liquid olefin-heating oil to 1 volume of catalyst per hour (1 v./v./hr.). The space velocity may vary between about 0.5 and 5 volumes of liquid olefin-hydrocarbon oil per volume of catalyst per hour. The amount of olefin on the heating oil may vary between about 0.211 and 1:02 by volume (liquid) or about 0.1: 1 and 1:0.2 by weight.

Under these conditions, mercaptans, sulfides, disulfides and other reactive sulfur compounds in the heating oil are converted to hydrogen sulfide. The hydrogen sulfide then further reacts with the olefin to form the corresponding mercaptan. Where propylene is the olefin used, propyl mercaptan is formed.

The apparatus shown in FIG. 1 is especially adapted for desulfurizin'g heating oil and for producing propyl mercaptan at the same time. However, the process used in connection with the apparatus of FIG. 1 is not restricted to the addition of propylene only, as other low boiling olefins up to C olefins may be used instead of propylene or in addition to propylene. In the process used in connection with FIG. 1, a necessary requirement is that the boiling range of the mercaptan product must be below the initial boiling point of heating oil so that the mercaptan may be recovered in high purity by a single fractionation.

The total efiiuent is withdrawn from the bottom of reactor 10 through line 16 and passed into the upper portion of stripper vessel 18 where the excess olefin, hydrogen sulfide and mercaptan are stripped out overhead. The stripping agent which may be steam is introduced into the lower portion of stripping vessel 18 through line 22 for upward passage countercurrent to the downfiowing higher boiling heating oil. The stripping agent is preferably makeup olefin and is the olefin which is used as the reactant in reactor 10 for reaction with the sulfur in the hydrocarbon oil being treated. Where the olefin used as a reactant is a low boiling olefin such as propylene, for example, the stripping gas introduced through line 22 comprises the low boiling olefin or propylene which may be pure propylene or impure propylene containing other compounds or other olefins. However, with an impure olefin stream, the purity of the mercaptan produced will be correspondingly reduced. V

The stripping vessel is maintained at a temperature between about 50 F. and 350 F. and under a pressure between about atmospheric pressure and 200 p.s.i.g. The heating oil product substantially lowered in objectionable sulfur compounds and having less than 2 mercaptan number is withdrawn from the bottom of stripping vessel through line 24.

The stripped out materials comprising olefin, H 8 and mercaptan pass overhead through line 26 into condenser 28 to cool the materials to a temperature between about 50 F. and 200 F. and to condense the mercaptan product while unreacted and make-up propylene or other olefin is recycled through lines 36 and 14 along with any unreacted hydrogen sulfide to reactor 10. The condensing temperature depends on the mercaptan and is intermediate to that required to condense the mercaptan but not the olefin. The cooled mixture is passed to gas-liquid separator 32 to separate liquid mercaptan which is withdrawn from the bottom of separator 32 through line 34. The separated gases including olefin or olefins and hydrogen sulfide pass overhead through line 36 for recycle through line 14 to reactor 10. It is to be noted that here the low boiling olefin such as propylene is used both as a stripping gas in stripping vessel 18 and also as a reactant in reactor 10. When the olefin and corresponding mercaptan boils at a higher temperature range than the sulfur-containing hydrocarbon oil, steam is used as the stripping gas.

Referring now to FIG. 2, which is especially adapted for desulfurizing naphtha and producing, for example, a mercaptan such as dodecyl mercaptan at the same time but not restricted thereto, the reference character 42 designates a line for feeding a hydrocarbon distillate such as high sulfur naphtha or the like having a boiling range between about 90 F. and 400 F. into recycle line 44 containing a high boiling recycled olefin, such as C olefin. Other olefins can be utilized to produce other mercaptans, as long as the olefin boils above the high sulfur hydrocarbon oil. Olefin make-up is introduced into line 44 through line 45. The resulting mixture is introduced into the top of reactor 46 containing sulfided cobalt molybdate on alumina catalyst. The same catalyst is used here as described above in connection with reactor 10. The temperature in reactor 46 is between about 400 F. and 700 F., the pressure is between 100 p.s.i.g. and 1000 p.s.i.g., the liquid space velocity is between about 0.5 and parts by volume of liquid fed to reactor 46 per part by volume of catalyst per hour.

The reaction products are withdrawn from the bottom of reactor 46 through line 48 and passed into the upper portion of fractionating column 52 for fractionating the reaction products into desulfurized naphtha which is withdrawn as a side stream through line 54. The pressure in the fractionator 52 can be between about 0 p.s.i.g. and 200 p.s.i.g. Steam as as stripping means is introduced as the bottom portion of the fractionator 52 through line 56 to strip out hydrogen sulfide which leaves the fractionator 52 overhead through line 58 and is recycled through line 44 to reactor 46. The bottom of the fractionator 52 is at a temperature between about 300 F. and 600 F. and

the top of the fractionator is between about 50 F. and 250 F.

The bottoms from fractionator 52 contain relatively high boiling unreacted olefin or olefins and the mercaptan corresponding to the olefin. Use of an olefin mixture will produce a mixture of different mercaptans. The boiling range of the olefins must not overlap the boiling rang of the mercaptans as otherwise low purity mercaptans will be produced. The mercaptan in the bottoms fraction is higher boiling than the naphtha feed and hence is taken off from a lower region than naphtha from the fractionator 52.

The bottoms fraction is withdrawn from the bottom of fractionator 52 through line 64 and introduced into the intermediate region of a second fractionator 66 to separate the high boiling mercaptan from the unreacted olefin or olefins. Here also the olefin has a lower boiling point than the mercaptan formed to permit easy separation of the olefin from the mercaptan. Fractionator 66 is at a pressure between about 0 p.s.i.g. and 200 p.s.i.g. The temperature at the bottom of fractionator 66 is between about 400 F. and 600 F. and the temperature at the top of the fractionator 66 is between about 300 F. and 500 F.

In the fractionator 66 the mercaptan such as dodecyl mercaptan is separated from gaseous material and is withdrawn from the bottom of fractionator 66 through line 68. The separated gaseous material comprising the unreacted olefin or olefins is passed overhead through line 72 and is recycled through line 44 to reactor 46. When higher than C olefins are used, such as G olefins, the corresponding mercaptans will be produced such as C mercaptans.

Laboratory experiments have been carried out with a 50-50 volume mixture of C olefins and heavy naphtha feed containing 0.7 wt. percent sulphur in the form of ethyl disulphide. The ethyl disulphide was added because the initial mixture was almost sulphur free. The feed mixture was processed over sulphided cobalt molybdate catalyst which initially before sulfiding was comprised of 3.5 wt. percent cobalt oxide, 12.5% molybdenum oxide and 84% alumina. The reactor efiiuent was analyzed for total sulfur and mercaptan sulphur contents to determine the conversion of ethyl disulphide to mercaptans. A reaction temperature of about 500 F. is preferred. At this temperature, 64% conversion to mercaptans was obtained.

The heavy naphtha feed had a boiling range of about 300 F. to 410 F. and was a virgin stream derived from atmospheric distillation of crude oil. The C olefins were produced by fractionating (15 theoretical plates, 10 reflux ratio) a C to C olefinic stream from the catalytic cracker to yield a 65 to 98 F. VT (vapor temperature) fraction. The composition of this C olefin concentrate is as follows:

In this experiment, the mercaptan product was not recovered quantitatively. The amount of mercaptan in the reactor effluent was measured by titration with silver nitrate solution. A sample of the reactor efiluent, was treated with 30 Baum NaOH solution to extract the mercaptans. After neutralizing the caustic with hydrochloric acid, an oily substance was produced which was analyzed on the chromatograph. N-amyl mercaptan and isoamyl mercaptan were positively identified. (Other C mercaptans also existed but could not be confirmed due to lack of suitable standards.)

In an actual plant unit, the amyl mercaptans would be recovered by apparatus such as shown in FIG. 1. Amyl :tremely high mercaptan number of 120 and would not be mercaptans have boiling points ranging from 210 to 260 R, which are intermediate and do not overlap the boiling range of the C olefins and heavy virgin naphtha.

The catalyst is that above described.

Results of the experiments are given in the following 5 Table 1.

TABLE 1.S YNTHE SIZIN G ME RCAPTANS Feed: Equivolume mixture of O olefins and heavy naptha containing (Cali-02S; Treat Conditions: 300 p.s.i.g.; 1.1 liquid volume of feed/volume of catalyst/tin; temp. as ind.

Catalyst: Sulphided CoMo on A1203 (See above) 1 Include mercaptans that were formed.

Efiect of treat temp. Effect of feed sulphur concentration Treat Temp. F 400 500 600 500 500 500 Feed:

Total sulphur wt. percent 0.74 0.74 0.74 2. 4 3. 5 7. 4 Mercaptan sulphur wt. percent n Nil Nil Nil Nil Nil N11 Total Product: 1

Total sulphur wt. percent 0.70 0. 72 0.71 2. 2 3. 1 7.0 Mercaptau sulphur wt. percent 0. 0. 47 0. 27 0. 69 1. 00 1. 48

Difference 2 Q. 0. 50 0. 0. 44 1. 51 2. 10 5. 52

Conversion, percent: Disulphide to mercaptan 27 64 36 29 28 20 LV percent C5H11SH on feed 3 0.6 1. 3 0.8 2.0 2. 8 4. 2

2 After removal of mercaptans from product (0 olefins and heavy naphtha after treatment) sulphur level is estimated to be ditlerence between total and mereaptan sulphur.

3 Calculated from mercaptan sulphur analysis on rotal product and assuming only amyl mercaptans were formed.

hydrogen sulfide produced in situ.

The hydrocarbon feed in the experiments reported in Table 2 was a 300640." F. sour gas oil which had an exmarketable unless it was sweetened. Other sour gas oils having other boiling point ranges such as 300 to 725 F.

and other mercaptan numbers such as 10 to 150 may be used. Obviously, with lower mercaptan number gas oils,

lesser amount of propyl mercaptan would be produced. In these experiments the treattemperature was varied from 300 F. to 700 F. while maintaining other variables such as space velocity, pressure and proylene to gas oil ratio constant. In these runs the preferred temperature is between about 500 F. and 600 F. The mercaptan number of the 300 F.+ gas oil fraction was reduced from 117 to 9 and .5, respectively, as to 500 F. and 600 F., a reducextent of 8.35 weight percent. Since pure propyl mercaptan would have a sulfur content of 42 weight percent, the

purity of our product is about 20% propyl mercaptan.

The concentration of the mercaptans can be raised by improved fractionation efiiciency.

Although 2.4 LV percent of a 20% mercaptan concentration solution does not appear considerable, it should be noted that processing units built for sweetening gas oils are generally in the range of 5000 to 10,000 b./d. capacity. On this basis, about 25 to 50 b./ d. of pure mercaptans could be produced and this would be quite an appreciable amount.

In the experiment, the whole mixture of gas oil feed and propylene in equal volume ratio was passed through the catalyst bed. The product from the treatment went into a separator maintained at about 30 F. to 40 F. range wherethe propylene was allowed to flash ofi through a knockout trap maintained at 32 F. and a condensing trap maintained at minus F. The first trap prevented any loss of propyl mercaptans and the second trap served to condense the unreacted propylene. The contents from the first trap were combined with the liquid product from the separator and fractionated (15 theoretical plates, 5 reflux ratio) to produce the fractions indicated in Table 2.

TABLE 2.MERCAPTAN PRODUCTION CONOURRENILY WITH GAS OIL SWEETENING Feed: SOD/640 F., gas oil R811 No.) Propylene/feed: 0.29 liquid vol. propylene/vol. gas oil Operating conditions:

otjvjhr. on combined propylene and gas oil feed p.S.l.g. Unconverted propylene recycled COMO-A1203 catalyst; sulphided Gas oil Depropanized liquid product Pure feed H SH Experiment No 5 4 2 3 8 300 400 500 600 700 LV, percent Nil Nil Nil 2. 4 1. 7 0.7 RSH No. 5, 679 6, 458 3, 017 RSH-S Wt. percent 2 8. 35 8. 51 4. 29 42.0 225/300 F. cut:

LV, percent 1. 8 2. 2 2. 9 5. 4 4. 3 2. 4 RSH No 189 269 1, 543 58 138 300 F. plus cut:

LV, percent 98. 2 97. 8 97. l 92. 2 94. 0 RSH No 117 98 89 9 5 Total S. wt. percent 0.84 0. 79 0. 76 0.67 0. 57

ESE No. 100

wt. percent.

Spec. grav. of fraction 1,000

2 Mereaptan sulphur wt. percent on init./225 F. out.

Mercaptan sulphur on the various fractions was determined by silver nitrate titration and total sulfuron the 300 F. plus cut by the method described by ASTM D 155258 T.

The pressure in carrying out experiments similar to those reported in Table 2 can be varied between about 100 and 1000 p.s.i.g. (pounds per square inch gage). The space velocity can be varied between about 0.5 and 5 v./v./hr. (volumes of liquid feed per volume of catalyst per hour). The propylene to gas oil feed ratio can vary between about 02:1 and 1:02 on a liquid volume basis. Instead of propylene, other olefins or olefin mixtures such as ethylene, butenes, pentenes and hexenes may be used.

In addition, a few experiments have been carried out on a blend consisting of LV percent C olefins (C tetramer) and 90 LV percent of an acid treated parafiim'c oil. The C olefins possess a distillation range of 375-425 F. and the parafiinic oil, a distillation range of about 500-700 F. Carbon disulfide was added to this blend to the extent of 1 weight percent sulfur and the total mixture was passed through a heated reactor packed with sulfided cobalt molybdate on alumina catalyst. Operating conditions were 600 F., 300 p.s.i.g. and 1 LHS (liquid hour space velocity for the mixture).

Dodecyl mercaptans were identified but were not recovered from the product by distillation. From the mercaptan numbers of the total products, it was estimated that about 0.2 to 0.6 LV percent on feed of dodecyl mercaptan were produced.

On the process associated with FIG. 2, the C olefin has a lower boiling point than the C mercaptan and so the mercaptan can be separated by fractionation and re moved as a bottoms product. The separated olefin passes overhead and is recycled to the reactor.

In other experiments, a parafiinic oil having a boiling range of 500700 F. was used rather than naphtha. The paratfinic oil boiling range is above that of C mercaptans which'have a boiling rangeof about 440 to 480 F. In the laboratory experiment, the total product (C mercaptan plus unreacted C olefins plus parafiinic oil) was actually fractionated under vacuum to yield a 400-5 00 F. (atmospheric pressure cut). Chromatograph analyses on this cut positively identified normal and tertiary C mercaptans.

While sulfided cobalt molybdate on alumina is the only catalyst mentioned, other desulfurizing catalysts may be used.

What is claimed is:

1. A method of removing sulfur from parafiinic naphtha as a mercaptan consisting essentially of the steps of admixing at least one C olefin with the naphtha, passing the mixture over sulfided cobalt molybdate on alumina in a reaction zone at an elevated temperature and pressure, fractionating the reaction products to separate desulfurized naphtha as product from hydrogen sulfide and from a bottoms'fraction containing C olefin and C mercaptan, recycling at least part of said hydrogen sulfide to said reaction zone, separating said bottoms fraction into a C mercaptan fraction as product and C olefin and recycling said C olefin to said reaction zone.

2. A method according to claim 1 wherein the temperature is between about 400 F. and 700 F. and the pressure is between about 100 p.s.i.g. and 1000 p.s.i.g.

3. A method according to claim 2 wherein the temperature is about 500 F. and the pressure is about 200 p.s.i.g.

4. A method of removing sulfur from parafiinic naphtha as a mercaptan consisting essentially of the steps of admixing an olefin having a higher boilingpoint than said naphtha, passing the mixture Over sulfided Cobalt molybdate on alumina in a reaction zone at an elevated temperature and pressure to form a mercaptan, fractionatforming mercaptans consisting essentially of the steps of admixing with a heating oil an olefin having a lower boiling point than said'heating oil, passing the mixture over a catalyst comprising sulfided cobalt molybdate on alumina in a reaction zone at an elevated temperature and pressure, to form a mercaptan having a lower boiling point than said heating oil, passing the resulting reaction products to a stripping zone, introducing a stripping gas into the lower portion of said stripping Zone for upward flow therethrough and utilizing as at least a part of a stripping gas a lowerboiling olefin of the same numberof carbon atoms as said admixed olefin, removing desulfurized oil from the bottom of said stripping zone, removing overhead a mixture of olefin, hydrogensulfide' and mercaptan, recovering mercaptan from an olefin and hydro.- gen sulfide mixture. and recycling said last mentioned mixture to said reaction zone.

7. A method according to claim 6 wherein said elevated temperature is between about 400 F. and 700 F. and

- the pressure is between about 100 p.s.i.g. and 1000 p.s.i.g.

8. A method according to claim 6 wherein said olefin comprises propylene, said temperature is between about 500 F. and 600 F. and the recovered mercaptan comprises propyl mercaptan.

9. A method of removing sulfur from naphtha as a mercaptan consisting essentially of the steps of admixing a C olefin with the naphtha, passing the resulting mixture over sulfided cobalt molybdate catalyst on alumina'in a reaction zone at an elevated temperature and pressure, recovering desulfurized naphtha and a C mercaptan as product.

10. A method for desulfurizing virgin hydrocarbon distillates boiling in the range of 800 F. and for recovering the sulfur as a'mercaptan consisting essentially of the steps of:

(A) admixing an olefin having aboiling range difierent from that of the distillate with the. distillate,

(B) passing the mixture over sulfided cobalt molybdate on alumina catalyst in a reaction zone at a temperature in the range of 400-700" F. and a pressure in the range of -1000 p.s.i.g. whereby a mercaptan having a boiling range different from that of the distillate is formed as one of the reaction products,

(C) separating desulfurized distillate and mercaptan,

' and (D) recovering the two products.

References Cited UNITED STATES PATENTS DETBERT E. GANTZ, Primary Examiner.

SAMUEL P. JONES, Examiner.

12/1964 Davis et a1. 208-2 16 

1. A METHOD OF REMOVING SULFUR FROM PARAFFINIC NAPHTHA AS A MERCAPTAN CONSISTING ESSENTIALLY OF THE STEPS OF ADMIXING AT LEAST ONE C12 OLEFIN WITH THE NAPHTHA, PASSING THE MIXTURE OVER SULFIDED COBALT MOLYBDATE ON ALUMINIA IN A REACTION ZONE AT AN ELEVATED TEMPERATURE AND PRESSURE, FRACTIONATING THE REACTION PRODUCTS TO SEPARATE DESULFURIZED NAPHTHA AS PRODUCT FROM HYDROGEN SULFIDE AND FROM A BOTTOMS FRACTION CONTAINING C12 OLEFIN AND C12 MERCAPTAN, RECYCLING AT LEAST PART OF SAID HYDROGEN SULFIDE TO SAID REACTION ZONE, SEPARATING SAID BOTTOMS FRACTION INTO A C12 MERCAPTAN FRACTION AS PRODUCT AND C12 OLEFIN AND RECYCLING SAID C12 OLEFIN TO SAID REACTION ZONE. 